{"version":"2.1.247","anchor":"plumbing-calls-and-passthrough-mcp-tools-described-in-the-pr","canonical_anchor":"plumbing-calls-and-passthrough-mcp-tools-described-in-the-pr","heading":"Plumbing calls and passthrough MCP tools: described in the protocol, not yet served","tier":"soon","area":"Remote Tools","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.247\/e\/plumbing-calls-and-passthrough-mcp-tools-described-in-the-pr","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.247","markdown":"### Plumbing calls and passthrough MCP tools: described in the protocol, not yet served\n\nThe attached-machine protocol describes plumbing calls and passthrough MCP tools that this build cannot serve.\n\n**What**\n\nThe protocol for tools on an attached machine describes two things this build cannot do. One is a plumbing call, a tool call made by the session's own machinery rather than by Claude, described as being only directory sync's file-sync tool today. The other is carrying the machine's own MCP tools in an announcement, which the schema itself says are carried but not yet served.\n\n**Details**\n\n- The plumbing request appears only in the schema, in a host-side validator that rejects it as agent-originated, and in two message classification lists. No code answers one.\n- The file-sync tool named in the description does not exist anywhere in this build.\n- The surrounding remote-tools feature is gated on the account flag `tengu_violin_wood`, compiled in as off, so none of this is reachable without a server value.\n\n**Evidence**\n\n`carried now, not yet served over this channel.`\n\n- Flag `tengu_violin_wood`: Off in both readings (read for one account on one subscription tier against v2.1.247; this account: off, anonymous baseline: off, compiled default: off)\n- Area: Remote Tools\n- Tier: Nothing to try yet\n- Useful: 1\/5\n- Signal: 4\/5\n- Present in the build but not switched on"}